1. Field of the Invention
The invention relates to a display; in particular, to a display apparatus and a voltage calibration method.
2. Description of the Prior Art
Please refer to FIG. 1. FIG. 1 illustrates a schematic diagram of the driving method of the ramp source driver in the conventional display apparatus.
As shown in FIG. 1, in the conventional display apparatus using OLED On Silicon micro-display technology, the ramp source driver generates a ramp voltage VRAMP through a ramp voltage generator RVG and transmits the ramp voltage VRAMP to all data lines DL(X) through a buffer BF.
When the value counted by the ramp counter RCT is equal to the default value stored in the data register DTR (for example, both are N), the switch SW coupled between the buffer BF and the data line DL(X) is turned off immediately. At this time, the voltage on the data line DL(X) is the voltage value of the ramp voltage VRAMP generated by the ramp voltage generator RVG.
However, in fact, in this circuit architecture, the following factors may cause the voltage values sampled on the data line to be inconsistent.
At first, the ramp voltage generator RVG basically charges the fixed capacitor through a fixed current source to generate a ramp voltage VRAMP having a fixed rising slope (as shown in FIG. 2), thereby providing different gray scale voltages required for the display panel. However, since the current source and the capacitor will change with the variation of process, voltage and temperature, the ramp voltage VRAMP provided by different driving circuits will have different rising slopes, which needs to be improved.
In addition, the ramp counter RCT is coupled to the oscillator OSC, and the oscillator OSC provides oscillator frequency to the ramp counter RCT. Since the oscillator OSC also changes with the variation of process, voltage and temperature, the time at which the switch SW is turned off each time (for example, T shown in FIG. 2) is inconsistent, so that the ramp voltage values sampled on the data line DL(X) are also different and need to be improved.